class_docstr: Wrap an errno style error.
  
  Parameters
  ----------
  errno : int
      The ZMQ errno or None.  If None, then ``zmq_errno()`` is called and
      used.
  msg : string
      Description of the error or None.
code: def __str__(self):
      return self.strerror
  
imports: from errno import EINTR
label_desc: Use image node_id 2 for calling the ZMQError obj's underlying member method code with example usage: obj.__str__() and returns: self